Rites

In the Catholic church a non-priest can take the confession of a dying person (could a non-Catholic?).  But, you need a priest to give you Holy Communion, as well as to perform the other rites of 'extreme unction' (the shorthand for which is extramunction).  Now, extreme unction need not be performed only when one is dying.  It can be administered to those who are merely sick.  Here's what I don't know ... what's the difference (in the Catholic Church) - if any - between last rites and extreme unction?